Image forming apparatuses that form images using erasable coloring materials have been put into practical use. As the erasable coloring materials, coloring materials are known that become transparent by being heated. For example, an image forming apparatus forms an erasable full-color image by using erasable coloring materials of black (BK), cyan (C), magenta (M), and yellow (Y).
The above-described image forming apparatus cannot form an image when the coloring materials are insufficient. For example, in the image forming apparatus, an image forming operation is stopped even when only one of the coloring materials out of the erasable coloring materials of BK, C, M, and Y is insufficient.